ORA-38800: Cannot start Redo Apply on the open physical standby database
Cause: An attempt was made to start Redo Apply on an open physical standby database instance.
Action: Make sure the primary database is at compatibility 11.0.0 or higher. The redo logs to be recovered on an open physical standby database must be generated at compatibility 11.0.0 or higher. If you have any redo below 11.0.0 to be applied on the standby, you must apply them on a mounted standby before restarting recovery on an open standby when the log format advances to 11.0.0 or higher. If this is a RAC standby database, make sure the ACTIVE_INSTANCE_COUNT parameter is not set.